Make A.C 220 Volt Automatic Stabilizer Using Arduino NANO or UNO




Introduction: Make A.C 220 Volt Automatic Stabilizer Using Arduino NANO or UNO

About: I like to make things in free time

In this instructables, I will show you how to make automatic voltage stabilizer using Arduino NANO that will show AC voltage, watt, steps, transformer temperature & auto fan on-off for cooling.

This is 3 steps Automatic Voltage stabilizer

My configuration

1st steps is normal/output

2nd steps adds 20 V to output

3rd steps adds 50 V to output

Warning !
A.C high voltage can kill you, if you are not careful what you are doing & I will not suggest electric beginner to do this, unless you are qualify and have idea what you are doing.

Step 1: Part List and Requirement

1 - Arduino NANO -> Amazon link

1 - Voltage Sensor -> How to make it

1 - DC to DC steps down, Buck Converter -> Amazon link

1 - 5v Relay Module -> Amazon link

1 - Current sensor ACS712 -> Amazon link

1 - LCD 16x2 module -> Amazon link

2 - 10k preset -> Best to buy it from local stores cheap price.

3 - 16v 1000uf capacitor -> Best to buy it from local stores cheap price.

1 - 220ohm resistor -> Best to buy it from local stores cheap price.

1 - zener diode 5.1v -> Best to buy it from local stores cheap price.

5 - 1N4007 diode -> Best to buy it from local stores cheap price.

1 - Stabilizer Transformer -> How to make your Own See the youtube tutorial -> Or buy from your local store. Note -: transformer must have 12v output for controllers.

I made 800va transformer by buying parts from local stores, and my transformer have 3 steps, step 1 is normal/output, 2nd steps increase 20v, and 3steps increase 50v.

~~! MOSFET that use in fan -> 600V N-Channel Power MosFET, and its works!!

~~! DC-DC steps down, Buck Converter used for Arduino for stable 5V power.

Step 2: Schematic, Diagram & Connection

As the circuit diagram you see above, I change a bit for stability & add other components in same board for less space.

Connect & Soldier parts according to the schematics.

Connection :-

Input transformer 12v line to the circuit -> 12VAC in mark area.

input Sensor connections

Connect Voltage sensor positive to A0 pin of arduino and Negative to ground

Connect Current Sensor Vcc pin to 5v line, Gnd pin to gnd line and out pin to A1

Connect Temperature Sensor LM35 Vcc pin to 5v, Gnd pin to gnd line and data pin to A2

Connect toggle switch as show in diagram, middle pin to A3, right pin with 10k resistor to GND, left pin to 5v line.

output connections Relay

Connect Arduino D7 to relay pin1

Connect Arduino D8 to relay pin2

Connect Arduino D9 to relay pin3

Connect Arduino D10 to Relay Pin 4

LCD connections

LCD - D7 -> Arduino D2

LCD - D6 -> Arduino D3

LCD - D5 -> Arduino D4

LCD - D4 -> Arduino D5

LCD - RW -> Arduino D6

LCD - E -> Arduino - D11

LCD - RS -> Arduino D12

Relay to transformer connection

Connect as shown in diagram above.

Download Circuit Diagram Below Fritzing

Step 3: Coding & Describing Codes

Introduction of codes, & what it will do

It will monitor AC voltage through pin A0 of arduino and control which relay to be active in that time. Example -> If arduino get 199VAC then it will active relay 1 which will increase voltage to 219VAC. In brief if voltage is less than 210 and also greater than 180 it will active relay 1 which will boost 20V, If voltage is greater than 210 and less than 230 it will deactivate relay 1.

The monitoring AC voltage will also display on LCD, and it also display output voltage by adding steps voltage to input voltage which will show the output voltage. Note:- output voltage is less accurate when more load is connect because there is no sensor on output voltage.

ACS712 module sense how much current is drawn from output, then arduino will calculate in watt and show in to the LCD display.

It also monitor temperature of the transformer, if temperature is getting high of the set point, it will turn on the fan.

Download code from github

I hope You will like this instructables

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    Question 11 months ago

    Please how are we suppose to power the voltage sensor ?


    Answer 5 weeks ago

    Its directly powered by main AC


    5 months ago on Step 1

    bro how i can edit the ACS712.cpp you can make a video?


    8 months ago

    hi ! this instruction is nicely done, have a query, am using an manual stablizer 7.5kv @ 220v having 8 steps. voltage swing from 165 to 290v all of sudden hence cant be used, trying to use with 8 relay with 40amps ( available online micro-controller has only 4 relay control). can you help? awaiting your reply.

    Pepito PAYET
    Pepito PAYET

    1 year ago


    I am looking for what type of transformer to buy but I cannot find it, is there a specific name? Or if you have a link please? I saw the video to build one but I prefer to buy one. I tried: "Tri pole transformer, tri pole stabilizer".


    Fayad fajokh
    Fayad fajokh

    1 year ago

    How ican chose the transformer


    2 years ago

    Is this useful for home electrical items


    Reply 2 years ago

    Yes, I am using till now for my P.C and its works fine.


    2 years ago

    please which transistor was used at the fan terminal and again what was the dc-dc convertor used to power. im new to this project please help me


    Question 3 years ago

    how many watts can this handle? and what would i have to do or upgrade to make it handle 3,000 watts? I actually only need a max of 2,400 watts but 3kw sounds about right.


    Answer 3 years ago

    It can Handle Max 1,500Watts.
    If you want to upgrade then change Relay (High Amp), Transformer 3,000Watts or more and also Need some changes in codes specially how much voltage is deliver by transformer in each steps you have to declare in code